Temperature and irradiation species dependence of radiation response of nanocrystalline silicon carbide
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Kumar Sridharan Engineering Physics Department, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; and Materials Science and Engineering Department, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
Steve Shannon Nuclear Engineering Department, North Carolina State University, Raleigh, North Carolina 27695, USA
Izabela Szlufarskaa) Materials Science Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; Materials Science and Engineering Department, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA; and Engineering Physics Department, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA (Received 27 June 2014; accepted 24 October 2014)
The grain size dependence of the radiation response of silicon carbide (SiC) has been studied under 1.0 MeV Kr21 ion irradiation. It was found that radiation resistance decreased with grain refinement, in contrast to previous studies on the same nanocrystalline (nc) SiC material using Si ion and high voltage electron irradiation. The effect of grain size on radiation response may depend upon the ion species used due to a potential change in amorphization mechanism. It was also determined that temperature had a strong effect on the grain size dependence of the radiation response in SiC due to the activation temperatures of critical recombination and migration reactions. This work explores the possible impacts of irradiation species, temperature, and experimental design on the radiation response of SiC.
I. INTRODUCTION
Silicon carbide (SiC) has many properties that make it a desirable candidate material for applications in nuclear energy systems. These properties include chemical resistance, high temperature mechanical stability, high thermal conductivity, and low neutron cross-section.1 SiC has a wide range of potential applications including the fission product barrier layer in tristructural isotropic (TRISO) fuels,2 first wall and cladding material,3 and use as matrix material for actinide burning.4 Improving the radiation stability of SiC would further enhance its suitability for these applications. One avenue for improving radiation resistance is refining the grain size to the nanometer length scale. Nanocrystalline (nc) materials have a high density of grain boundaries (GBs), which are known to act as sinks for point defects generated during irradiation. Increasing the sink density results in more efficient elimination of these defects, potentially leading to an increased radiation resistance. A number of studies in both metals5–9 and ceramics5,10,11 have already shown the expected improvement in radiation resistance upon grain size reduction, a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2014.340 J. Mater. Res., Vol. 29, No. 23, Dec 14, 2014
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making this approach a potential path for improving the radiation resistance of SiC. There have been a few studies investigating the effect of grain refinement on the radiatio
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